The invention relates to devices and methods for selecting network nodes for a cellular communication network. It further relates to methods and devices for modifying information scored in said devices for selecting.
In cellular communication networks of the so-called “third generation” new architectures become possible. Said architectures are to allow simplified network adaptations co changing requirements. An important aspect of the new architectures is that so far fixed hierarchic connections between the network nodes are replaced by dynamic hierarchic connections. Fixed connections exist in GSM (Global System for Mobile communication) networks, for instance, between base station controllers and radio base stations or base station subsystems and mobile services switching centers, where each mobile services switching center cooperates with predefined base station subsystems.
Communication networks can be split into core networks and access networks and service networks.
The change to dynamic connections affects the cooperation within core networks and access networks as well as between them.
A core network consists of at least one network node, which offers a telecommunication service or administration service, a so-called core network node. The tasks of a core network are, for example, the switching of connections, the mobility management, the charging data acquisition and the storage and administration of subscriber data. Nodes of a core network are, for example, mobile services switching centers, GPRS (General Packet Radio Service) support nodes, home location registers and service control nodes.
An access network is a network enabling at least one subscriber to have access to a core network. Common tasks of an access network are the administration of access resources such as radio frequency channels, the measurement of connection qualities and the cooperation with a core network. Nodes of an access network are, for instance, base station controllers, radio base stations and radio network controllers.
Service networks comprising network nodes for supporting services surpassing the switching of connections are regarded in the present application as a part of the core network. Nodes of said networks are regarded as core network nodes.
One example is the cooperation between core network nodes and access network nodes in networks being constructed according to a new architecture, for instance, so-called “third generation networks”. The cooperation between said nodes is handled more flexibly. Thus, no longer only one core network node can cooperate with a plurality of access network nodes, a so-called 1:N relation, but now rather a plurality of access network nodes can cooperate with a plurality of core network nodes in a so-called N:M relation. The technical report of the Third Generation Partnership Project 3G TR 23.922 version 1.0.0, published in October 1999, describes the introduction of cellular communication networks, wherein the connections between network nodes are based on the internet protocol. The internet protocol realizes the dynamic connections between network nodes. A press release by the company Ericsson of Feb. 1, 2000 describes the improved flexibility of this architecture. The architecture makes it possible to react on requests such as, for instance, temporary inhomogeneous traffic load, more flexibly.
It is prior art technology, that by means of the fixed connections between the network nodes, specific network nodes are allocated to each network node within a communication network for cooperating purposes.
U.S. Pat. No. 5,557,029 describes a system and a method for selecting a network node for handling a call in a network with said fixed connections. However, the system and the method are adapted to select a network node in a network with said fixed relation and are not capable of performing a selection in a network with an n:m relation between access network nodes and core network nodes.
Thus, the problem is avoided that a selection has to be made from a plurality of network nodes, for instance, with connection setups, location updates or handovers. This problem arises only with the dynamic allocation of network nodes to each other. Another difficulty resides in the provision of service information. According to the prior art technologies said information are stored in the respective network nodes, in which they are needed. To maintain this solution means—in the case of dynamic allocation—that each network node has to store the service information of all network nodes, with which it can cooperate.
Service information of a network node comprise, data on the service area and the routing area being serviced by the network node, as well as information on the node as such. This is, for instance, the emergency call center, which is switched in the routing area in the case of an emergency, the billing origin and the call origin, both being geographical data on a caller, wherein the first data is required for drafting the bill and the second data is required for processing the call, and local call restrictions, if a subscriber is allowed to phone only in a certain area. The Standard GSM 03.08 version 7.2.0 for handling subscriber data, published in 1998, describes location information and local call restrictions.
The multiple storage of service information of all network nodes brings about the disadvantage that unnecessarily large quantities of data are stored and that said information have to be kept consistent with a large amount of work.
In accordance therewith it is the object of the invention to provide methods and devices for an improved cooperation between network nodes in a cellular communication system.
Moreover, it is an object of the invention to develop methods for providing network nodes with service information on additional network nodes, if required also on service areas or routing areas, in a simplified manner.
It is an advantage that available processing capacities can be optimally exploited. A more even utilization of network nodes is achieved.
It is particularly advantageous that network nodes independently verify internal states and, if required, independently send messages for updating the corresponding entries in selection devices and configuration databases. This facilitates the registration of new nodes and allows a high updating of the data by involving only a small extent of administrative work.
It is moreover advantageous that the well-known data base technology is used. This reduces development costs and avoids downtimes caused by development errors.
Especially advantageous is the enabling or disabling of the selection of nodes by operator commands or settings.
Equally advantageous is the use of a configuration database which enables the provision of service information with a high data consistency and with a small extent of administrative work. Especially advantageous is the automatic updating of the data in a selection device by network nodes, which enables the automatic integration of new network nodes, or of network nodes which had been defect in the meantime, in a communication network.
The storage of free capacities proves to be an advantage. This enables a deliberate selection of network nodes.
Moreover, it proves to be an advantage if only data from network nodes with free capacities are stored. This reduces the number of data records, which have to be administered and searched through in a selection device.
Particularly advantageous is the consideration of distances between network nodes which avoids unnecessarily far connections within a network, thereby saving network capacities.
Furthermore advantageous is the storage of preferred allocations of network nodes in a selection device, which avoids unnecessary accesses to the node capacity memory and possible distance calculations.
Also advantageous is a service information memory. It enables the provision of service information for network nodes in a simple manner.
Further advantageous is the storage of service information in a network node, which avoids unnecessary transmissions of service information and service information requests thereby reducing the data traffic through the network. Equally an advantage is the sending of service information, e.g. by means of a selection device, which reduces the signaling work as no data have to be requested, and it ensures the availability of information in due time.
Another advantage is the automatic sending of service information by a configuration data base, which combines the advantage of the punctual availability of the service information with the advantage of the small extent of administrative work for a central facility.
Further advantageous is the modification of data stored in a node capacity memory for a group of network nodes. By this the selection of several nodes can be enabled or disabled by a single action. This reduces the number of necessary actions for a modification.
Another advantage is the sending of a list of access network nodes after a modification. By this user equipment gets the latest information about valid nodes that can be contacted. This avoids unnecessary attempts to contact invalid nodes or increases the choice of nodes to contact.
Especially advantageous is the contacting of a preferred network node prior to sending a network node request. This reduces the number of network node requests to be processed.
Especially advantageous is the storage of a list of preferred network nodes. This reduces the number of network node requests and thus reduces the data traffic through the network.